In order to improve the performance of velocimeter, the front-end circuit design of laser velocity target was proposed. The PIN photodiode array was used as the sensors of the receiving part of the laser screen targets. According to the characteristics of the PIN photodiode, the preliminary amplification circuit was designed, which could transfer the faint optical signal to electrical signal and amplify the signal preliminarily. Put forward a new technology in which the error-elimination PIN array. And the instrument amplification circuit was used to conduct the successive amplification. The result shows the method can decrease the influence of the environmental factors, and enhanced the system noise-signal ratio (SNR) and improved the performance of laser velocimeter.